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Comparing libev/ev.pod (file contents):
Revision 1.455 by root, Wed Jun 26 00:01:46 2019 UTC vs.
Revision 1.458 by root, Fri Dec 20 20:51:46 2019 UTC

… …
480unblocking the signals. 480unblocking the signals.
481 481
482It's also required by POSIX in a threaded program, as libev calls 482It's also required by POSIX in a threaded program, as libev calls
483C<sigprocmask>, whose behaviour is officially unspecified. 483C<sigprocmask>, whose behaviour is officially unspecified.
484 484
485This flag's behaviour will become the default in future versions of libev. 485=item C<EVFLAG_NOTIMERFD>
486
487When this flag is specified, the libev will avoid using a C<timerfd> to
488detect time jumps. It will still be able to detect time jumps, but takes
489longer and has a lower accuracy in doing so, but saves a file descriptor
490per loop.
491
492The current implementation only tries to use a C<timerfd> when the first
493C<ev_periodic> watcher is started and falls back on other methods if it
494cannot be created, but this behaviour might change in the future.
486 495
487=item C<EVBACKEND_SELECT> (value 1, portable select backend) 496=item C<EVBACKEND_SELECT> (value 1, portable select backend)
488 497
489This is your standard select(2) backend. Not I<completely> standard, as 498This is your standard select(2) backend. Not I<completely> standard, as
490libev tries to roll its own fd_set with no limits on the number of fds, 499libev tries to roll its own fd_set with no limits on the number of fds,
… …
1535 1544
1536Many event loops support I<watcher priorities>, which are usually small 1545Many event loops support I<watcher priorities>, which are usually small
1537integers that influence the ordering of event callback invocation 1546integers that influence the ordering of event callback invocation
1538between watchers in some way, all else being equal. 1547between watchers in some way, all else being equal.
1539 1548
1540In libev, Watcher priorities can be set using C<ev_set_priority>. See its 1549In libev, watcher priorities can be set using C<ev_set_priority>. See its
1541description for the more technical details such as the actual priority 1550description for the more technical details such as the actual priority
1542range. 1551range.
1543 1552
1544There are two common ways how these these priorities are being interpreted 1553There are two common ways how these these priorities are being interpreted
1545by event loops: 1554by event loops:
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1749when you rarely read from a file instead of from a socket, and want to 1758when you rarely read from a file instead of from a socket, and want to
1750reuse the same code path. 1759reuse the same code path.
1751 1760
1752=head3 The special problem of fork 1761=head3 The special problem of fork
1753 1762
1754Some backends (epoll, kqueue, probably linuxaio) do not support C<fork ()> 1763Some backends (epoll, kqueue, linuxaio, iouring) do not support C<fork ()>
1755at all or exhibit useless behaviour. Libev fully supports fork, but needs 1764at all or exhibit useless behaviour. Libev fully supports fork, but needs
1756to be told about it in the child if you want to continue to use it in the 1765to be told about it in the child if you want to continue to use it in the
1757child. 1766child.
1758 1767
1759To support fork in your child processes, you have to call C<ev_loop_fork 1768To support fork in your child processes, you have to call C<ev_loop_fork
… …
4484 4493
4485 ev_select.c only when select backend is enabled 4494 ev_select.c only when select backend is enabled
4486 ev_poll.c only when poll backend is enabled 4495 ev_poll.c only when poll backend is enabled
4487 ev_epoll.c only when the epoll backend is enabled 4496 ev_epoll.c only when the epoll backend is enabled
4488 ev_linuxaio.c only when the linux aio backend is enabled 4497 ev_linuxaio.c only when the linux aio backend is enabled
4498 ev_iouring.c only when the linux io_uring backend is enabled
4489 ev_kqueue.c only when the kqueue backend is enabled 4499 ev_kqueue.c only when the kqueue backend is enabled
4490 ev_port.c only when the solaris port backend is enabled 4500 ev_port.c only when the solaris port backend is enabled
4491 4501
4492F<ev.c> includes the backend files directly when enabled, so you only need 4502F<ev.c> includes the backend files directly when enabled, so you only need
4493to compile this single file. 4503to compile this single file.
… …
4614available and will probe for kernel support at runtime. This will improve 4624available and will probe for kernel support at runtime. This will improve
4615C<ev_signal> and C<ev_async> performance and reduce resource consumption. 4625C<ev_signal> and C<ev_async> performance and reduce resource consumption.
4616If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc 4626If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
46172.7 or newer, otherwise disabled. 46272.7 or newer, otherwise disabled.
4618 4628
4629=item EV_USE_SIGNALFD
4630
4631If defined to be C<1>, then libev will assume that C<signalfd ()> is
4632available and will probe for kernel support at runtime. This enables
4633the use of EVFLAG_SIGNALFD for faster and simpler signal handling. If
4634undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
46352.7 or newer, otherwise disabled.
4636
4637=item EV_USE_TIMERFD
4638
4639If defined to be C<1>, then libev will assume that C<timerfd ()> is
4640available and will probe for kernel support at runtime. This allows
4641libev to detect time jumps accurately. If undefined, it will be enabled
4642if the headers indicate GNU/Linux + Glibc 2.8 or newer and define
4643C<TFD_TIMER_CANCEL_ON_SET>, otherwise disabled.
4644
4645=item EV_USE_EVENTFD
4646
4647If defined to be C<1>, then libev will assume that C<eventfd ()> is
4648available and will probe for kernel support at runtime. This will improve
4649C<ev_signal> and C<ev_async> performance and reduce resource consumption.
4650If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
46512.7 or newer, otherwise disabled.
4652
4619=item EV_USE_SELECT 4653=item EV_USE_SELECT
4620 4654
4621If undefined or defined to be C<1>, libev will compile in support for the 4655If undefined or defined to be C<1>, libev will compile in support for the
4622C<select>(2) backend. No attempt at auto-detection will be done: if no 4656C<select>(2) backend. No attempt at auto-detection will be done: if no
4623other method takes over, select will be it. Otherwise the select backend 4657other method takes over, select will be it. Otherwise the select backend
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4686backend for GNU/Linux systems. If undefined, it will be enabled if the 4720backend for GNU/Linux systems. If undefined, it will be enabled if the
4687headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled. 4721headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
4688 4722
4689=item EV_USE_LINUXAIO 4723=item EV_USE_LINUXAIO
4690 4724
4725If defined to be C<1>, libev will compile in support for the Linux aio
4726backend (C<EV_USE_EPOLL> must also be enabled). If undefined, it will be
4727enabled on linux, otherwise disabled.
4728
4729=item EV_USE_IOURING
4730
4691If defined to be C<1>, libev will compile in support for the Linux 4731If defined to be C<1>, libev will compile in support for the Linux
4692aio backend. Due to it's currenbt limitations it has to be requested 4732io_uring backend (C<EV_USE_EPOLL> must also be enabled). Due to it's
4693explicitly. If undefined, it will be enabled on linux, otherwise 4733current limitations it has to be requested explicitly. If undefined, it
4694disabled. 4734will be enabled on linux, otherwise disabled.
4695 4735
4696=item EV_USE_KQUEUE 4736=item EV_USE_KQUEUE
4697 4737
4698If defined to be C<1>, libev will compile in support for the BSD style 4738If defined to be C<1>, libev will compile in support for the BSD style
4699C<kqueue>(2) backend. Its actual availability will be detected at runtime, 4739C<kqueue>(2) backend. Its actual availability will be detected at runtime,

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